The invention is based on a fuel injection valve for internal combustion engines. In one such fuel injection valve, known from German Offenlegungsschrift DE-OS 39 28 912, a valve member is guided axially displaceably in a guide bore of a valve body that protrudes by one end into the combustion chamber of the engine to be supplied. On its end toward the combustion chamber, the valve member has a valve sealing face, which cooperates with a valve seat formed on the end toward the combustion chamber of the guide bore. Adjoining the valve seat face in the direction remote from the combustion chamber is a fuel-carrying high-pressure conduit in the valve body, which is formed partly by an annular gap between the valve member shaft and the wall of the guide bore. Toward the combustion chamber, at least one injection opening adjoins the valve seat; the flow of fuel between the high-pressure conduit and the injection opening is opened up by the raising of the valve member from the valve seat.
For cooling the valve member, a diversion conduit is also provided in the valve member, by way of which the high-pressure conduit communicates continuously with a relief chamber when the valve member is lifted from the valve seat, and which is formed by a blind bore that begins toward the end of the valve member toward the combustion chamber and a transverse bore that intersects the blind bore. The transverse bore discharges into a diversion chamber formed between the valve member and the wall of the guide bore; this chamber is defined axially by an injection valve shim that rests on the valve body, and a through opening is provided in the shim in such a way that the diversion chamber communicates continuously with a relief chamber formed by the spring chamber of the injection valve.
This continuous communication, in the open position of the valve member, between the high-pressure conduit and the relief chamber has the disadvantage, however, that a relatively large amount of fuel flows out via the diversion conduit during the actual injection event and is thus unavailable for the fuel injection, which impairs the efficiency of the entire system. Moreover, because of the undefined amount of leakage at the diversion conduit, the quantity of fuel to be injected can be metered only very imprecisely, so that the known fuel injection valve does not meet the demands of modern internal combustion engines.